1. Technical Field
The present invention relates in general to the field of medical lancet devices used for obtaining droplets of blood samples for testing and diagnostic applications. More particularly, the invention relates to a tip for a blood lancet device that is adjustable between several distances for varying the depth of skin puncture by a lancet needle.
2. Description of the Related Art
The use of lancets and lancing devices are well known in the art as a convenient and safe means for piercing or pricking a person's skin to draw small amounts blood that can then be subjected to a variety of medical tests such as for blood sugar content. A typical integrated lancet design is described in U.S. Pat. No. 3,358,689, with a lancet needle encased in an elongated plastic body. Known integrated lancet assemblies having adjustable tips are described in U.S. Pat. Nos. 6,530,937 and 6,558,402 and 5,916,230 and 6,419,661. Typical lancet assemblies depict a cylindrical housing containing a spring-loaded assembly that is activated by a button on the housing's exterior surface. Upon activation, the lancet needle is thrust deeper into the unit's tip and the needle protrudes from an opening on the top of the tip. The lancet needle exits the opening for puncturing a patient's skin. Following activation and extension of the lancet needle through the tip opening, the spring retracts to its natural state of equilibrium and causes the lancet to retract inwards. When the spring is at rest, the needle tip no longer extends through the tip opening. The tip is necessarily removable so that a used lancet may be removed and discarded and a fresh lancet inserted into the tip for the next use. In one common design, the unit is pen-shaped and has a screw-on tip for easy removal. Lancet devices having this configuration are disclosed in U.S. Pat. Nos. 6,558,402 and 5,613,978
Lancing devices are designed to draw a relatively minute quantity of blood from capillaries immediately below the surface of the skin and are commonly used by patients is themselves at home as well as by medical professionals in medical offices and hospitals.
These devices are also used in medical office and hospital settings in order avoid the necessity of having to re-sterilize the mechanical device and/or lancet after each use. Lancing devices are specifically designed to safely accommodate their purpose as “pricking” devices that are commonly utilized by non-medically trained individuals including children. Specifically, in order to effectuate a safe and controlled puncturing of a patient's skin, the exposed tip of the needle extends only a very short distance (typically a few millimeters) from the flat upper surface of the lancet body, which acts as a bearing to limit the puncture depth.
A problem arises, however, concerning the depth of the lancet needle extending from the lancet assembly and the depth of the corresponding penetration it makes into a patients' skin. Lancet devices that do not allow for adjusting the depth of penetration can be undesirable. There is a need for an adjustable depth lancet device to accommodate patients having different skin thicknesses and different levels of pain tolerance.
For example, Chinese Patent ZL 01263172.8 discloses an adjustable head lancet tip. However, the invention of that reference utilizes five separate components: an end cover and an adjustable shell comprised of a front cover, a rear ring, and a split barrel having upper and lower sides. This unit is complex and requires several steps during manufacturing and assembly. After molding, the adjustable shell's four components must be assembled and permanently joined using the added step of applying a sealing method such as sonic welding. The newly formed and assembled adjustable shell must also be mounted onto the end cover. Additionally, the disclosure teaches the use of two separate and independent components for effectuating the varying length of the tip and for creating the detent that holds the tip at each depth setting. Thus, this reference does to not teach an assembly that provides a single functional unit for accomplishing both of these features in a manner that can be manufactured using only two molded pieces that may be snapped together without the added step of sonic welding.
U.S. Pat. No. 6,451,040 discloses an adjustable lancet device end cap. The disclosure of this reference teaches the use of a base cap and an end cap to accomplish adjustability and the detent. However, like the Chinese reference described above, those features are accomplished separately and independently. The reference discloses the use of one or more fingers located on the end cap, and the detent is positioned on a post located on the end cap that comes into clicking contact with slots formed on the twist cap. Additionally, the apparatus, as depicted in this reference is relatively complex and not suitable for attachment to generally available cylindrically shaped lancet devices.
It can therefore be appreciated that a need exists for an improved lancing design that overcomes the foregoing problems. The present invention addresses such needs.
A primary object of the invention is to provide an adjustable tip for a blood lancet device capable of use with conventional and generally available and relatively inexpensive lancets.
A further object of the invention is to provide an adjustable tip for a blood lancet device capable of use with conventional and generally available and relatively inexpensive lancet devices, whereby an existing lancet devices' tip may be readily replaced by the adjustable tip of the present invention.
A further object of the invention is to provide an adjustable tip for a blood lancet device which is simple in design and relatively inexpensive to manufacture by only using two parts that may be snapped together.
A further object of the invention is to provide an adjustable tip for a blood lancet device which provides a visible indication of each of the various depths of skin puncture so the user can accurately set the adjustable tip prior to usage.
A further object of the invention is to provide an adjustable tip for a blood lancet device which provides an audible indication when the tip is adjusted from one depth to another so the user can readily and easily confirm when the tip has been adjusted to a different depth.
A further object of the invention is to provide an adjustable tip for a blood lancet device which provides a tactile sensory indication when the tip is adjusted from one depth to another so the user can readily and easily confirm when the tip has been adjusted to a different depth.
A further object of the invention is to provide an adjustable tip for a blood lancet device wherein the means for adjusting the tip, the means for holding the tip in each particular position and the means for indicating to the user that the tip has been adjusted to another depth setting are all integrated as a single functional unit within the tip.
A further object of the invention is to provide an adjustable tip for a blood lancet device which provides stabilization of the adjustable tip such that the tip remains locked at each particular depth setting and avoids slipping and resulting punctures at unintended depths.